A quick explanation of the numbers: They refer to the "specific absorption rate" or SAR, a common benchmark that measures the rate of radiofrequency energy your body gets from the phone. The lower the number, the lower the radiation exposure. For a phone to be certified by the FCC and sold in the U.S., for example, its maximum SAR level must be less than 1.6 watts per kilogram.

And there's still no conclusive evidence that a phone with a higher SAR level poses a greater health risk -- or any health risk at all -- than a model that emits less radiation.

(These lists were compiled by the Environmental Working Group, a lobbying group that advocates on behalf of public health and the environment, based on data provided by the phone manufacturers. The data are up to date as of December, which means some newer models aren't listed. For the group's full list of phone models, click here.)

Some other high-profile phones fared somewhere in the middle on the rankings. The SAR level of the Apple iPhone 4 was 1.17 W/kg (for the AT&T model; the Verizon model wasn't listed). Exposure levels for the dozens of BlackBerry models varied widely.